L-ascorbic acid is an essential nutrient. It is well known that L-ascorbic acid plays an important role with respect to the encephalon, and the following literature references have reported its effectiveness against various diseases of the cranial nerve. For example, the use of L-ascorbic acid to treat schizophrenia is reported in M. Herjanic, Orthomolecular Physiatry, D. Hawkins and L. Pauling, ed. W. H. Freemann, San Francisco, pp. 303-315 (1973); the use of L-ascorbic acid to treat chronic alcoholism is reported in S. K. Majumder et al., "International J. Vitamin", Nutr. Res. 51, 274-278 (1981); the administration of L-ascorbic acid to oligophrenic children including those having Down's syndrome is reported in R. H. Harell et al, Proc. Natl. Acad. Sci., U.S.A., 78:1, 574-578 (1981); the use of L-ascorbic acid to reduce the adverse reaction of L-dopa as a drug for the treatment of parkinsonism is reported in W. Sacks, G. M. Simpson, "Ascorbic Acid in Levodopa Therapy", The Lancet. March 1, 527, 1975; and the use of L-ascorbic acid in ameliorating depression in conjunction with adrenocortico-tropic hormone therapy is reported in P. Cocchi et al, "Antidepressant Effect of Vitamin C.", Pediatrics, 65, 4: 862--862 (1980).
In recent years, ascorbic acid has been studied with respect to its activity as a water-soluble scavenger of intracerebral radicals which are considered to cause ischemic reperfusion disorder, a sequela of a cardiac infarction operation, angina pectoris, cerebral apoplexy and cerebral infarction. Thus, ascorbic acid is known to have a therapeutic effect on intracerebral radical disease.
Considering these effects on the brain, L-ascorbic acid has hitherto been administered to treat various conditions. However, when administered perorally or by phleboclysis, due to the presence of the blood brainbarrier, L-ascorbic acid in the blood may fail to reach the cerebral cells in a sufficient amount, and the desired effect on the brain by administering L-ascorbic acid cannot be satisfactorily achieved.